Denis Barbier give me this solution : remove any libX* files in /lib/ and restart X. All must run OK now :-)
We don't know why this files put here, but remove them are solve my problem. Another workaround : # ln -s /usr/share/X11/XKeysymDB /usr/X11R6/lib/X11/XKeysymDB let back the keyboard with XkbRules "xorg" for me. But the problems with the mouse, DPMS, QT are linked with the files /lib/libX* (there're not need for this symbolic link once these files are removed). Thank to Denis Barbier and Jeff Lessem, and the Debian X Strike Force. Aurélien LPR.
